I have been using the D700 for three years and the capabilities of this camera continue to amaze me. I don't consider 12MP to be limiting in any way, even with a 30" wide gamut monitor. For landscape photography, I really don't want to have a 36MP camera, since with FX you already can notice an IQ degradation due to diffraction between F/5.6 and F/8, while with a 12MP camera this only occurs between F/11 and F/16.
In your present situation I suggest that you get a wa lens that is suitable for landscape. If you don't need filters, the Nikon 14-24/2.8 is an excellent choice; it is sufficiently wide for use with a DX camera. Then wait a year and see what kinds of FX bodies are available.